ETC is among companies being called out by activists over ties to the Myamar military, which seized power from the elected government in a Feb. 1 coup, sparking widespread protests in the country and international condemnation.

Singapore is the biggest source of foreign investment into Myanmar, according to the governments of both countries.

Singapore-headquartered payments firm Coda told Reuters on Friday it had deactivated military-linked telecom operator Mytel from its portfolio of payment channels. This means that Mytel customers cannot make purchases using Coda's services.

ETC is developing a commercial and residential project in Myanmar called Golden City, which is being built on land leased from the Myanmar army.

The development has a total tenure of 70 years, including extensions, after which the entire project transfers to the lessor - the army's office of the quartermaster general, according to ETC's annual report.

ETC, through a subsidiary, paid $24.9 million for a 49% stake in Golden City.

Trading in ETC shares, which are listed on SGX's Catalist platform for smaller companies, were halted through Friday.

The stock closed Thursday at S$0.034.

The company did not respond to a request for comment.

In its report, rights group Justice for Myanmar said Golden City "channels millions of dollars" to the army.

SGX's queries include requiring ETC to elaborate on its fundraising efforts, status updates and details of the Golden City project by March 1.

The SGX also told ETC to put on hold a proposed placement exercise and other fundraising activities until it provides clarity on issues raised by the report.

(Reporting by Aradhana Aravindan in Singapore; Editing by Ed Davies)